I've been looking to invest in my first mastering compressor (with tubes) for awhile. After a bunch of research, I bit the bullet and picked up an IGS Tubecore 3U and shot it out with the A-Design Nail (that I  had on demo). I also swapped out the stock IGS tubes for NOS Sylvania 5670s. Here is my take...

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PROS: Build quality is superb and screams quality. Big tactile knobs and the infamous Elma switches, SC HPF (off, 60Hz, 120Hz), and wet/dry mix knob. The meters are nice, big, and orange. The M/S mode is a unique feature that very few mastering compressor have. There are also two different types of transformers in this beast...Carnhill transformers (input) and Sowter transformers (output). You also have the ability to change tubes (stock, 5670, or the classic 6386 Fairchild tubes). What more can you ask for?  After swapping out the stock tubes for some 5670 Siemens tubes (5 star), calibrating the meters (super easy), and running mixes through it for the past few days, all I can say is Wow! The Tubecore is everything I wanted for warming and gluing my ITB mixes. The low-end sounds fuller and more focused. The mid-range is definitely beefed up. Vocals are noticeably more present and aggressive. Attach times range from 0.1ms to 30 ms. Release times range from 100ms to 4sec. It has very smooth compression but can also bounce (SSL style)  if need be. The mix knobs are golden. The M/S mode takes some experimenting with and depends on the quality of your source, but you can add serious width to your mix or subtly tame the side transients. I generally use the Brainworx BX Digital v3 for adding M/S width during mastering,  but to my ear I think the Tubecore does this better/more naturally. From now on, I'll probably only use the BX for rolling off lows on the sides and monoing the bass. 

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CONS: The only con I can think of is that I would have liked for there to be 'solo' switches for mid and side channels  (to quickly hear whats going on in either channel). However, you can just use the gain knobs (which feel awesome) so its no big deal. 

 

OVERALL: 5 Stars. The Tubecore is the complete package. I love what I"m hearing so far. Obviously, the A-Design Nail got returned. It was a great unit too, don't get me wrong, but it was much too fidgety to get the compression dialed in the way I wanted it and it didn't allow me to push the tubes (surprisingly). The Nail just didn't have the sound or the features I was after. YMMV. Hats off to Igor @ IDS. 

 

Link to IGS Website: http://www.igsaudio.com/tubecore-3u

See also my review on Reverb: https://reverb.com/item/30140892-igs-audio-tubecore-mastering-compressor-fairchild-tubes

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